• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.101-106
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• 2012

The press bulging process is very useful and productive method to produce round-type mechanical components which have not been able to be manufactured because of limitation of the conventional press technology. The application of the press bulging process has expanded very quickly in the hydraulic and electronic industry and more recently it has been used to produce other mechanical parts such as the automobile and shipping parts. This expanding application also has brought some unsolved problems and leads many researchers to put their effort into the die design of the press bulging process. In this study, to obtain the optimum die shape for the press bulging process, various process parameters have been considered such as corner radius, bulging height, pressing length, and forming load, etc. The main interest of this paper is to verify the press bulging process which has more than 4.0 in height-length ratio. From this aspect, Finite Element analysis shows great ability to simulate the precise deformation process and gives us manufacturing database. Consideration of strain, stress, and strain-rate for the various cases has been also taken to keep the forming load within a particular range.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.301-302
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.509-510
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.301-302
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• 2009

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.77-82
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• 2008

Rubbing-roller is used for manufacturing liquid crystal display, and static displacement of the rubbing-roller becomes bigger as length of the rubbing roller made of aluminum is getting longer. Therefore, material of the rubbing-roller is changed from aluminum to CFRP(Carbon Fiber Reinforced plastic). Recently thermal spraying is applied to manufacturing process of long rubbing-roller. The thermal spraying has disadvantages such as increment of manufacturing time and fraction defective caused by density of stainless steel particle. In this study, fitting process by drawing was suggested and FEM analysis with Tsai-Wu failure theory and fitting experiments are carried out to find adequate shrink allowance. The suggested shrink allowance gives proper adhesive force, and CFRP failure is not occurred. Furthermore, the fitting process is applied to long rubbing-roller and availability of the fitting process is studied by measurement of roundness, straightness and shear strength.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.43-49
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• 2015

This paper describes the design of a forged fitting form to acquire a method of product design measurement by target measurement standards. The pipefitting connects each pipe and combines seals and nipples with the pipes normally. Therefore, the section combined with the fitting pipe was measured by a 3D scanner, and the acquired measurement and the design measurement were obtained after modification of the forged fitting pipe by that standard. Moreover, the accuracy of the model was verified through leakage testing of the oil and verification of the design measurement for accuracy decisions on the design measurement after modification of the product.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.57-62
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• 2015

A large variety of pipe flanges are required in the marine and construction industry. Pipe flanges are usually welded or screwed to the pipe end and are connected with bolts. This approach is very simple and has been widely used for a long time; however, it results in high development costs and low productivity, and the products made through this approach usually have safety problems in the welding area. In this research, a new approach for forming pipe flanges based on cold forging and the floating die concept is presented. This innovative approach increases the effectiveness of the material usage and saves time and costs compared with the conventional welding method. To ensure the dimensional accuracy of the final product, finite element analysis (FEA) was carried out to simulate the process of cold forging, and orthogonal experiment methods were used to investigate the influence of four manufacturing factors (stroke of distance, pin die angle, forming of pipe diameter, and speed of the die) and predict the best combination of them. The manufacturing factors were obtained through numerical and experimental studies, which show that the approach is very useful and effective for the forming of pipe flanges and could be widely used in the future.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.140-145
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• 2015

In the present study, the structural safety of the bolt portion and collet tool structure of the pipe-fitting tool is analyzed by using the finite element technique. Two forces as piston forces with the magnitude of 187.5 Tons are applied to the inner and outer portions of the collet tool, respectively. A structural load of 750 Tons is applied to the bolt portion. In the analysis results, it is found that the structure becomes safe under the current loading conditions. The reliability rating of the pipe is calculated in this study. The material properties of the actual material are evaluated by using mechanical testing. Therefore, the material properties are used to carry out static structural and optimization analysis.